我已经阅读了许多示例,并最终使用以下代码从Java程序内部执行了命令行命令.
public static void executeCommand(final String command) throws IOException,
InterruptedException {
System.out.println("Executing command " + command);
final Runtime r = Runtime.getRuntime();
final Process p = r.exec(command);
System.out.println("waiting for the process");
p.waitFor();
System.out.println("waiting done");
try (final BufferedReader b = new BufferedReader(new InputStreamReader(
p.getInputStream()))) {
String line;
while ((line = b.readLine()) != null) {
System.out.println(line);
}
}
}
我已经用一个简单的ls命令测试了它,并且工作正常.当我尝试运行另一个命令时,它将永远耗费时间(保持运行25分钟,但尚未停止).
当我在命令行上执行tabix命令时,我得到以下统计信息
4.173u 0.012s 0:04.22 99.0% 0+0k 0+0io 0pf+0w
因此,它应该很快完成.
该命令是
time tabix file pos1 pos2 … pos190 > /dev/null
问题可能是tabix命令包含> / dev / null结尾?如果没有,什么原因可能导致此问题?
解决方法:
您需要先将阅读器附加到该流程,然后再调用它的waitFor.没有它,它可能会填满分配的输出缓冲区,然后阻塞-但仅对于大输出,小(例如测试)输出似乎很好.
public static void executeCommand(final String command) throws IOException, InterruptedException {
System.out.println("Executing command " + command);
// Make me a Runtime.
final Runtime r = Runtime.getRuntime();
// Start the command process.
final Process p = r.exec(command);
// Pipe it's output to System.out.
try (final BufferedReader b = new BufferedReader(new InputStreamReader(p.getInputStream()))) {
String line;
while ((line = b.readLine()) != null) {
System.out.println(line);
}
}
// Do this AFTER you've piped all the output from the process to System.out
System.out.println("waiting for the process");
p.waitFor();
System.out.println("waiting done");
}